<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>壁纸</title>
    <script>
        var num=1;
        function changeIng() {
            var img=document.getElementById("lbt")
            img.src="img/"+(++num==6?num=1:num)+".jpg";
        }
    </script>
</head>
<body onload="setInterval('changeIng()',1000)">
<img id="lbt" src="img/1.jpg" width="100%">
</body>
</html>
